So I am looking for the best way to join .125 Dia stainless wire. I have no welding or brazing equipment as of now and am looking to do this as cheaply as possible. The whole purpose is that I am looking to start building "rolling ball sculptures" (ex. http://www.rollingballsculpture.com/ ) It seems welding or brazing is the preferred method but i have been pricing gas setups and they are a bit more than i had hoped for once you factor in the bottles. I have experience with brazing, mig, tig, and limited stick welding so i am not worried about the learning curve side of things. I guess my one other option would be to put together a home made spot welder as i have seen plans online for several but no sure how well it could end up handling the .125 stainless. Hope someone can help me sort this all out.
You could look around for a wire butt welder or in a pinch a 3/4" bandsaw blade welder might do the trick with some jaw mod's to get perfect repeatable alignment.
Around 3-5KVA rating should be sufficient for 1/8" SS. You only need a tack so you shouldn't need to add argon gas to prevent oxidation or grinding the upset off. It takes some talent to get a weld upset ground without gouging the wire or keeping it cosmetically flaw free. A bit of a learning curve could get you something acceptable.
The problem with resistance welding SS is the weld is somewhat brittle, so avoid bends in weld areas. You could try annealing in the welder after welding. Use a bit of scotch bright pad to remove the coloring for good to go.
Those little MAPP gas welders should would do the silver soldering too.
Learn cause and effect through experience. Mastering those relationships is the "Common Sense" ability within the art of any trade.